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Factory alarm on a 91?

D

DieselSJ

NAXJA Forum User
Location
QC AZ
Just scored a 91 Briarwood. Hooked up a new battery and the alarm goes off (not turns off, it activates and makes noise and flashes the lights, etc...). I did not get any kind of remote for it - the owner lost it and just has the keys.

How can I tell if it is a factory or aftermarket alarm? If factory, how do I disable it? I won't physically be with the vehicle until next weekend - I've got a friend that is working on getting it running for me.
 
Update - it is a factory alarm. According to the DSPO, they had (key work being "had") a special key with a chip in it that would disable the alarm when you put it into the ignition. They also had a remote but it stopped working and the dealer couldn't get the system to function, and it was recommended that they pull the system entirely.

So the question becomes can I disable it by just pulling the fuse, and if I do disable it will that also disable the ignition?
 
I really don't understand what you're saying... one post you say its factory the other you say there's a chip in the key. And what's a DSPO?

There is no chip in the key on a 1991 factory security system.

Just attach your battery cable and while the lights are flashing insert the key into the ignition and cycle the key a few times without turning over the motor and it should reset and disable the security system so you can start your XJ.

The key alone disables the security system when you insert the factory key into the driver door or rear hatch locks (when system is enabled and locked) and cycle the key. You can enable the system when leaving the vehicle by cycling the auto door locks to "lock" and shutting the driver door.

You can simply lock the driver door with the nob or the key and the security system is bypassed.

You don't need the remote transmitter to make the factory system work.

.
 
DieselSJ said:
Update - it is a factory alarm. According to the DSPO, they had (key work being "had") a special key with a chip in it that would disable the alarm when you put it into the ignition. They also had a remote but it stopped working and the dealer couldn't get the system to function, and it was recommended that they pull the system entirely.

So the question becomes can I disable it by just pulling the fuse, and if I do disable it will that also disable the ignition?
Click to expand...
As said, there is no chip inside the '91 factory key. I too have a '91 Briarwood with this alarm.
To disable it, you should pull the "sentry alarm module" which I believe is located in the upper portion of the driver's wheel well, on the tranny tunnel side, but I'm not near my FSM and I haven't looked at the location in a while.

bchulett said:
I really don't understand what you're saying... one post you say its factory the other you say there's a chip in the key. And what's a DSPO?

There is no chip in the key on a 1991 factory security system.

Just attach your battery cable and while the lights are flashing insert the key into the ignition and cycle the key a few times without turning over the motor and it should reset and disable the security system so you can start your XJ.
Click to expand...
Actually no. The factory alarm disables the vehicle from starting. The only way to disable the alarm is to insert the key into either the driver or passenger door, or the rear hatch provided the sensors are still attached to the lock cylinders.

bchulett said:
The key alone disables the security system when you insert the factory key into the driver door or rear hatch locks (when system is enabled and locked) and cycle the key. You can enable the system when leaving the vehicle by cycling the auto door locks to "lock" and shutting the driver door.
Click to expand...
Passenger door as well.

bchulett said:
You can simply lock the driver door with the nob or the key and the security system is bypassed.
Click to expand...
I know if you lock it with the nob from the inside, it will not arm the system, but I don't know about locking it with the key as there is a sensor on the lock cylinder that possibly could arm the system. I haven't used my '91 for some time now so I can't remember
 
Begster said:
I know if you lock it with the nob from the inside, it will not arm the system, but I don't know about locking it with the key as there is a sensor on the lock cylinder that possibly could arm the system. I haven't used my '91 for some time now so I can't remember
Click to expand...

I believe you are correct on that, can't remember if my briarwood armed when you use the door lock cylinder, but as far as i remember it did? Been way too long since i last used it.
 
Begster said:
Actually no. The factory alarm disables the vehicle from starting. The only way to disable the alarm is to insert the key into either the driver or passenger door, or the rear hatch provided the sensors are still attached to the lock cylinders.
Click to expand...

Yes understood. My reference is when you disconnect and reconnect the battery. Correct... you can reset or disable the system by rotating the key in the driver or passenger door lock. Cycling key in the ignition three times places the system into diagnostics mode... and I believe will also disable if done correctly. It's been awhile since I've had my battery disconnected and I believe at some point over the past 19 years, I've done it this way as well.

I have the 1991 Electrical, Heating-AC & Emissions Factory Service Manual... which includes the security system.. I won't rewrite the entire section here, its a complex network of functions and tests to confirm the system is operational.

Begster said:
I know if you lock it with the nob from the inside, it will not arm the system, but I don't know about locking it with the key as there is a sensor on the lock cylinder that possibly could arm the system. I haven't used my '91 for some time now so I can't remember
Click to expand...

I've owned my '91 XJ since new and know for fact if you lock the vehicle with the interior nob or [driver] exterior door lock, it does not arm the security system... locking the vehicle manually is how you bypass the security system.

And as we both said, cycling the key to the unlock position in the driver door lock or rear hatch lock, disarms the system.

.
 
Mbjeep91 said:
I believe you are correct on that, can't remember if my briarwood armed when you use the door lock cylinder, but as far as i remember it did? Been way too long since i last used it.
Click to expand...

If you use the interior [automatic] door lock switch to lock all the doors and shut the driver door it will arm the system.

I'd have to see the system demonstrating its "security" after locking it with the key. Using the exterior lock and key, I've never seen the security dash light blink for the defined xx seconds and I've never broken into my own vehicle to confirm the system is activated.

.
 
bchulett said:
Yes understood. My reference is when you disconnect and reconnect the battery. Correct... you can reset or disable the system by rotating the key in the driver or passenger door lock. Cycling key in the ignition three times places the system into diagnostics mode... and I believe will also disable if done correctly. It's been awhile since I've had my battery disconnected and I believe at some point over the past 19 years, I've done it this way as well.
Click to expand...
I see what you're saying now. Yep, I know about the diagnostics mode, but I have never gone into it so I haven't disabled the system that way. I actually tried going into diagnostic mode once, but it never worked.

bchulett said:
I have the 1991 Electrical, Heating-AC & Emissions Factory Service Manual... which includes the security system.. I won't rewrite the entire section here, its a complex network of functions and tests to confirm the system is operational.
Click to expand...

Ya, I do too. That test section was fun to read.


bchulett said:
I've owned my '91 XJ since new and know for fact if you lock the vehicle with the interior nob or [driver] exterior door lock, it does not arm the security system... locking the vehicle manually is how you bypass the security system.

And as we both said, cycling the key to the unlock position in the driver door lock or rear hatch lock, disarms the system.

.
Click to expand...

Ya, I know that doing it manually from inside will not arm the system, but I couldn't remember if the key did or not, which was why I said I wasn't sure. I was just thinking since there is the sensor on the door cylinder that disarms the system, I couldn't remember if it also armed the system as well.
 
if you want to disable the alarm system there is a maroon plug under the dash, if you look to the right of the steering column at the bottom of the dash there is a plug on the right un plug it. everything else will work fine, electric locks etc. but no alarm.

i dont know how this effects keyless entry, but it will disable the alarm, with no other ill effects.
 
DSPO - Dip Sh.. Previous Owner. As for the key with the chip, I'm just going by what they told me.

Note that they tried to cycle the key in the door locks and the ignition and it did not disable the alarm. The DSPO did confirm problems with the alarm and some huge estimate from the dealership to fix it which is why they parked it.

Good info about the Sentry module and the maroon plug. I did find a post on another forum that talked about grounding a wire that is in the driver's kick panel to disable the alarm. They tried that this morning and it shut off the alarm and it started and ran. I would feel much more comfortable if the entire system was out of the vehicle though.

Based on what I'm reading here, it is quite possible that the sensors on the door locks are bad and that is why it did not disarm with the key. That could also be why the prev owner couldn't disable it.

On a side note, anyone know where I can get a replacement fob?

Thanks for the help!
 
It may not be that easy. The last time I had mine replaced I had to go to the dealer to get it done. The unique number needed is on a tag inside the overhead console. You need to take that to a dealer and see if they can send it in to program a new fob - not sure where they send them.

Jeep changed the fobs in 1993 or thereabout so the dealers could do this...

Several years ago, there was a place on the internet.. can't find them at the moment.

.
 
DieselSJ said:
DSPO - Dip Sh.. Previous Owner. As for the key with the chip, I'm just going by what they told me.

Note that they tried to cycle the key in the door locks and the ignition and it did not disable the alarm. The DSPO did confirm problems with the alarm and some huge estimate from the dealership to fix it which is why they parked it.

Good info about the Sentry module and the maroon plug. I did find a post on another forum that talked about grounding a wire that is in the driver's kick panel to disable the alarm. They tried that this morning and it shut off the alarm and it started and ran. I would feel much more comfortable if the entire system was out of the vehicle though.

Based on what I'm reading here, it is quite possible that the sensors on the door locks are bad and that is why it did not disarm with the key. That could also be why the prev owner couldn't disable it.
Click to expand...
It is quite possible that they have fallen off the lock cylinders as well. My driver's door sensor keeps falling off, so when I use the key in the driver's door, it unlocks and I can open it, but it sets the alarm off.


DieselSJ said:
On a side note, anyone know where I can get a replacement fob?

Thanks for the help!
Click to expand...

Honestly, its not worth it. Those key fobs suck, and many times their maximum working distance is when they are pressed up against the glass window on the doors.
 
Begster said:
Honestly, its not worth it. Those key fobs suck, and many times their maximum working distance is when they are pressed up against the glass window on the doors.
Click to expand...

Even though the range sucks, still beats trying to thaw out my lock cyllinder after its all iced up from sitting outside all day in the winter.

The other plus is that all the doors unlock at once as opposed to unlocking your driver door and having all the passengers try to open theirs as you are hitting the power unlock switch, then locking and unlocking them again and there is still somebody who insists on trying to open their door causing you to go through the same routine again or reaching over and using the manual button.....
sure this has happened to most of us more than once!

Other than that they are pretty much useless!
 
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